Clusters of Galaxies in the First Half of the Universe from the IRAC Shallow Survey

Understand

We have identified 335 galaxy cluster and group candidates, 106 of which are at z > 1, using a 4.5 um selected sample of objects from a 7.25 deg^2 region in the Spitzer Infrared Array Camera (IRAC) Shallow Survey.

• Clusters were identified as 3-dimensional overdensities using a wavelet algorithm, based on photometric redshift probability distributions derived from IRAC and NOAO Deep Wide-Field Survey data.
• We estimate only ~10% of the detections are spurious.
• To date 12 of the z > 1 candidates have been confirmed spectroscopically, at redshifts from 1.06 to 1.41.